Heated windshields

[ghost rider]

OK, as my brain slowly warms up, I would like to add something. Brent, you have a concern about a short in the windshield. A heating element is a "controlled short" where the pos. and neg. leads are connected by a certain amount of resistance to produce heat. The entire windshield is a heating element with the pos. at one side and the neg. at the other. I don't see how doing a repair could possibly cause a "short". A short is sometimes confused with an open circuit which is what Glasseye is describing with the broken grid and should also not cause a problem except for a small spot that does not heat.

[SGT]

The number of heated windshields I have repaired I can count on two hands. Certainly not nearly as many as our British friends. Until this post, I did not know there were multiple heating element configurations or what they were labled. The ones I have done have been the grid style and I did not experience any problems.

For me when dealing with value added features such as heated windshields or rain sensors we should exercise common sense as we do with all repairs. To the best of my knowledge heated windshield elements are incorporated into typical laminated glass windshields. So if the damage can be safely repaired it should be treated as standard repair. The concern at that point is has the heating element or sensor been damaged to the point where the system is partially or entirely disabled. If the vehicle has redundant abilty to clear the windshield of the elements through the defroster or wiper switch, it is still safe to drive with the with the value added feature inop just as a vehicle that does not incorportate these features. Now... it becomes a customer call as to how important that feature is and whether they want to replace the windshield. For me, my primary concern is I leave the customer with a structurally sound repair and a safe vehicle.

To have a better undestanding, I would like to see illustrations and descriptions of these different types of elements and sensors so I know what to look for and how they operate to make the most educated decision to repair or not to repair. If they are even available.

Good thread Brent.

[Brent Deines]

OK, as my brain slowly warms up, I would like to add something. Brent, you have a concern about a short in the windshield. A heating element is a "controlled short" where the pos. and neg. leads are connected by a certain amount of resistance to produce heat. The entire windshield is a heating element with the pos. at one side and the neg. at the other. I don't see how doing a repair could possibly cause a "short". A short is sometimes confused with an open circuit which is what Glasseye is describing with the broken grid and should also not cause a problem except for a small spot that does not heat.

Please don't misunderstand. I am personally not at all concerned about windshield repair causing a short, and I agree with you 100%. My experience has been that if a wire is broken, or the film is damaged, that tiny area will not be heated so it may take a second longer to defrost, but that is do to the damage, not from the resin or the repair process. In the case of a screen printed line that is used to heat the wiper area, if the power is interrupted by damage to the line, it just fails to heat that line. I have repaired many defroster grids in my time simply by painting on a new line with electrically conductive paint. However, since it has been reported that windshield manufacturers do not recommend repairing some types of heated windshields, I cannot expose myself or Delta Kits to the liability of recommending the repair of heated windshields if the manufacturer advises otherwise.

If I understand it correctly the warnings from windshield manufacturers are that some heated windshield should be replaced rather than repaired because the damage could cause a short, not necessarily because the repair process will cause any harm. Please note that the warnings I have seen reported have been regarding specific types of heated windshields, not all heated windshields.

What I hope to find out from this thread is if any of the 1000+ windshield repair technicians that are members of this forum have ever experienced any problems with "any" type of heated windshield.

[SGT]

Brent,

That is good info. Certainly information that should be complied together or readily available to all techs who otherwise would never know exactly what they may be dealing with and how to proceed based on mfg reccomendations to avoid potential liability issues and an overall general but factual understanding of these systems.


Questions.

1. How many amps do these systems draw?

2. Are they wired in series or parallel?

3. Do the element leads connect connect inside the vehicle or other?

4. Do these systems have there own fuse or are they bundled with other equipment?

[Brent Deines]

I should make it clear that the only type of heated windshield that I have ever seen a warning for is the film type. Apparently if the film is damaged it could cause a short which could cause an overheating issue that could cause damage to wires, or even the electrical system. This seems like a design flaw that should cause the car and glass manufacturers to get pretty nervous to me.

Great questions Brian. I wish I had the answers, but the manufacturers have been slow to respond to my requests for more information.

Hopefully someone else on the windshield repair forum is more knowledgeable than I am about such things.

[Brent Deines]

So what I'm hearing is that most of the newer heated windshields that members of the windshield repair forum run across are the grid type, very few experienced technicians are passing them up, and no one has experienced any problems with them. Is that a fair assessment?

It doesn't sound like many of you have repaired many film type heated windshields, so it may be that they are not being used much these days.

I know there are still a number of vehicles that use the painted lines in the wiper area, but I don't think most of us mess with anything that was hit hard enough to damage both layers of glass as well as the laminate, so this type becomes a bit of a non issue.

My position remains unchanged, but it certainly would seem that there have been few, if any, instances of repairs "causing" a heated windshield to malfunction. However, that does not mean that certain types of heated windshields have not malfunctioned when damaged, or after the damage occurred, so I still recommend following the manufacturer recommendation. That appears to be the real challenge. How do we get either the glass manufacturer or the automobile manufacturer to issue a written recommendation, and if they do, will it be based entirely on safety concerns, or will that fact that both have the potential to profit from a replacement be a factor in issuing the recommendation.

It has always been my contention that at the very worst, a failed windshield repair does not improve the safety and cosmetics of damaged windshield, but a successful windshield repair never makes the damage less safe or cosmetically less appealing. I keep expecting to be proven wrong as there is an exception to every rule, but considering the number of repairs performed each year and the lack of evidence citing safety concerns, the windshield repair industry has an amazingly impeccable safety record.

[bill lambeth]

Brent,I repair range rovers all the time with the grids and I have never had any problems.